Puzzle #1: With Word 2003, when I open a file using the "Plain text" file
conversion option, Word assigns the "Plain Text" style to each paragraph,
which is not surprising; but it also applies direct font formatting
(confirmed via Reveal Formatting) so that the font is Courier New even
though I've redefined the "Plain Text" style to use Times Roman.

Puzzle #2: In Word 2000, I used to routinely open .HTM files with the "Text
file" conversion option. This option is no longer presented as an option in
Word 2003 when I select an .HTM file to open. (It *is* presented as an
option when I select a .TXT file.)